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Monthly climate in Rock Valley, Iowa, United States

Last updated: May 6, 2024

Under the Köppen–Geiger climate classification Rock Valley features a humid continental climate (Dfa).Temperatures typically range between -7 °C (20 °F) and 24 °C (75 °F) through the year, but rarely can drop to -31 °C (-23 °F) or can rise to as high as 36 °C (96 °F).The average annual precipitation amounts to about 877 mm (34.5 inches) and receives 94 rainy days on the 1 mm (0.04 inches) threshold annually.Rock Valley enjoys an average of 3071 hours of sunshine throughout the year, and daylight varies from 9 hours 0 minutes to 15 hours 19 minutes per day.

Monthly average temperatures in Rock Valley, Iowa, United States §

The warmest months in Rock Valley are June, July and August, with daily mean temperatures ranging from 22 to 24 °C (72 - 75 °F) throughout the day. The coldest temperatures usually occur in January, February and December, when daily mean temperatures range from -7 to -3 °C (20 - 27 °F) throughout the day. On average each year, Rock Valley experiences 85 days above 25 °C (77.0 °F) and 140 days below 0 °C (32.0 °F).

Monthly average temperatures with daily means, minimums and maximums for period, average high and low temperatures in Rock Valley, Iowa, United States.Generated using Copernicus Climate Change Service information.Data for period from January 2017 to June 2022.
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Maximum 12°C
(53°F)		 19°C
(67°F)		 25°C
(77°F)		 29°C
(84°F)		 34°C
(93°F)		 36°C
(96°F)		 36°C
(96°F)		 35°C
(96°F)		 33°C
(91°F)		 30°C
(87°F)		 25°C
(77°F)		 17°C
(62°F)
Mean maximum 9°C
(48°F)		 12°C
(54°F)		 20°C
(68°F)		 26°C
(79°F)		 31°C
(88°F)		 32°C
(90°F)		 34°C
(93°F)		 32°C
(90°F)		 32°C
(90°F)		 28°C
(83°F)		 18°C
(65°F)		 12°C
(53°F)
Average high -2°C
(29°F)		 -1°C
(30°F)		 7°C
(45°F)		 13°C
(56°F)		 20°C
(69°F)		 28°C
(83°F)		 29°C
(84°F)		 27°C
(81°F)		 24°C
(76°F)		 15°C
(58°F)		 7°C
(45°F)		 2°C
(35°F)
Daily mean -6°C
(21°F)		 -7°C
(20°F)		 2°C
(36°F)		 7°C
(45°F)		 15°C
(60°F)		 23°C
(73°F)		 24°C
(75°F)		 22°C
(72°F)		 19°C
(66°F)		 9°C
(49°F)		 2°C
(35°F)		 -3°C
(27°F)
Average low -11°C
(13°F)		 -12°C
(12°F)		 -3°C
(27°F)		 2°C
(35°F)		 10°C
(50°F)		 17°C
(63°F)		 19°C
(66°F)		 17°C
(62°F)		 13°C
(56°F)		 4°C
(40°F)		 -3°C
(26°F)		 -7°C
(19°F)
Mean minimum -23°C
(-9°F)		 -23°C
(-9°F)		 -14°C
(8°F)		 -8°C
(17°F)		 2°C
(35°F)		 10°C
(50°F)		 13°C
(55°F)		 11°C
(51°F)		 5°C
(41°F)		 -6°C
(22°F)		 -13°C
(8°F)		 -18°C
(0°F)
Minimum -31°C
(-23°F)		 -27°C
(-17°F)		 -26°C
(-14°F)		 -16°C
(3°F)		 -0°C
(32°F)		 6°C
(43°F)		 11°C
(52°F)		 8°C
(47°F)		 4°C
(39°F)		 -11°C
(12°F)		 -16°C
(4°F)		 -23°C
(-10°F)

Compare climate in Rock Valley with other places

Compare temperature, precipitation, sunshine, UV index in Rock Valley, Iowa, United States with other places around the world.

Monthly average precipitation in Rock Valley, Iowa, United States §

Rock Valley usually has the most precipitation in May, June and September, with an average of 11 rainy days and 111 mm (4.4 inches) of precipitation per month.The driest months in Rock Valley are January, February and November. On average, 27 mm (1.1 inches) of precipitation falls during these months.

Monthly average precipitation and precipitation days in Rock Valley, Iowa, United States.Generated using Copernicus Climate Change Service information.Data for period from January 2017 to January 2022.
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Average precipitation mm (inches) 25 (1.0) 29 (1.1) 70 (2.7) 92 (3.6) 133 (5.2) 101 (4.0) 80 (3.2) 98 (3.9) 100 (3.9) 85 (3.3) 27 (1.0) 39 (1.5)
Average precipitation days (≥ 1 mm) 4 6 7 9 15 10 8 9 8 9 5 4

Monthly sunshine hours in Rock Valley, Iowa, United States §

The sunniest months in Rock Valley are June, July and August, when the sun shines an average of 11 hours 25 minutes a day.Least sunny months in Rock Valley: January, November and December receive an average of 6 hours 11 minutes of sunshine daily.

Mean monthly sunshine duration, average sunshine hours per day and mean daily daylight hours in Rock Valley, Iowa, United States.Generated using Copernicus Atmosphere Monitoring Service information.Data for period from January 2017 to January 2022.
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Mean monthly sunshine hours 153 211 224 254 272 349 369 331 262 226 211 204
Mean daily daylight hours 9h 22m 10h 31m 11h 57m 13h 26m 14h 41m 15h 19m 14h 58m 13h 51m 12h 26m 10h 58m 9h 40m 9h 0m

Solar UV radiation in Rock Valley, Iowa, United States §

Rock Valley experiences the highest level of ultraviolet (UV) radiation in June, July and August, when the maximum UV index can reach values of 9 - 11, which corresponds to the Very High / Extreme category of sun exposure.January, November and December are in the Low / Moderate exposure category. In these months, the maximum values of the UV index do not exceed 3. For more detailed information, check out our hourly Rock Valley UV Index data.

Average daily maximum UV levels by month for Rock Valley, Iowa, United States.Generated using Copernicus Atmosphere Monitoring Service information.Data for period from January 2022 to January 2023.
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
UV Index (month maximum) 2 5 5 8 9 11 10 9 8 5 3 3